The focal length of lenses can vary significantly when subjected to temperature fluctuations. Germanium is a common material used in lenses operating in the infrared wavelengths due to its high refractive index and low dispersion. However, Germanium is very temperature dependant, having a thermo-optic coefficient (dn/dT) of nearly 400×10-6/° C., and therefore its performance quickly degrades with increasing temperature, becoming opaque at 100° C. Athermalization is important in optical systems for maintaining focus despite changes in temperature. Accordingly, there have been many attempts to design optical systems that are athermal. In particular, one approach is to design optical mounts and systems to compensate for the changing thermo-optic properties of the lenses.